In his new book Expository Exultation, John Piper describes the ultimate goal of the preacher:
The preacher speaks as a humble, authentic agent of Scripture. What it aims to produce, he aims to become. He aims to embody the worship the Bible seeks (1 John 4:23). And then he seeks to open his mouth and make the glories of God in Scripture as clear and beautiful as he can. By whatever grace he is given through the Holy Spirit, he devotes himself to expository exultation.